Currently, the above tasks are performed partly by commutator and commutatorless machines (M. M. Katsman, Guide to electric machines [Moscow: Academy, 2005, ISBN 5-7695-1686-0], p. 9). Commutator machines include universal electric machines and direct current machines, for example, those with permanent magnets and excitation winding. Commutatorless machines include synchronous and asynchronous electric machines, for example, those with squirrel-cage and phase-wound rotor, single-phase, three-phase, capacitor-type, reactive, hysteresis-type, linear and brushless rotor.
Among the above-mentioned machines, the most similar to the proposed machine are the brushless motors (see ibid., pp. 313-317) that include a rotor and a stator with their coils (phases) connected in parallel and have a thyristor (controlled) current feed to stator coils.
Phase machines (including brushless ones) are based on a relatively simple principle of operation: at first, maximum electric current is supplied to the first phase (a coil, or a system of coils), which makes the rotor turn by a certain angle. Then, similarly, maximum electric current is supplied to the second phase (a coil, or a system of coils). The rotor turns by a certain angle again, etc. Of course, electric current in the previous phase[s] (coil[s]) must be changed, for example, decreased; otherwise, the rotor will stop turning. Evidently, such a design does function, but is not optimal: not all the coils operate at full capacity at any moment.
Therefore, one must discontinue using such imperfect electric machines and use two-wire (single-phase, mostly direct) electric current only, with a full load of all winding coils (alternating electrical current has a large anti-induction and its power is smaller by a square root of two).